To convert a colour photo into black and white, we can use GIMP and apply afilter and do that job.

But, if you want to do the same for 1000 photos?what you will do?

You will get frustrated if you do it manually.won’t you?

Let us take a real problem.

Nowadays, we have a lot of Digital Photos from our digital cameras, mobilephones etc.

Most people have very high resolution cameras like 7 to 10 Megapixel cameras.The images are high in density and quality.They are upto 3-5 MB in size each.the resolution isThis high quality is good for printing.

But, we normally, we don’t print them all.we just view them, send via email, upload to picasaweb or flickr.

For viewing in the monitor, 800×600 resolution is enough.If we reduced the resolution, the file size will be automatically reduced.

the size of a 640×480 image is 57K only.we can reduce the file size from 5MB to 57K by reducing resolution.

How to reduce the resolution of all the images we have?going manually is hectic job.

Here the CLI tool rocks.

Imagemagick is software which contains a collection of small tools likeconvert, mogrify and more.

5 thoughts on “Resize your images using imagemagick”

What you’re talking about is image size, which is called “geometry” in ImageMagick.

Using identify (identify -verbose example_image.jpg ) we can see two very different pieces of information:

Geometry: 160×200 — which is the size of the image, width by height, and

Resolution: 360×360
Units: PixelsPerInch — which is the resolution.

Resolution is set by the -density command line option:

–density width
–density widthxheight

horizontal and vertical resolution in pixels of the image.

What resolution you use for an image is dependent on what you’re going to do with it: whether it’s for the web, for newspaper print production, or for high-end full color magazine or book print production.